Pulley device, in particular for tensioning idler or runner roller

ABSTRACT

A pulley device comprising a pulley and a bearing. The pulley has at least one “C-shaped” pulley part having an inner portion mounted on the bearing, an outer portion having an outer cylindrical surface dedicated to interact with a belt or a chain, and an intermediate portion extending substantially radially between axial ends of inner and outer portions on one axial side of pulley device. The outer cylindrical surface of outer ring is provided with at least one recess having in cross-section, a concave internal profile. The pulley part is provided with at least one protruding portion which inwardly extends beyond the inner cylindrical surface of inner portion. The protruding portion is received in a corresponding recess of outer ring so as to block the pulley part with respect to the outer ring in both axial directions.

CROSS-REFERENCE TO PRIORITY APPLICATION

This application claims priority to German patent application no.102017223317.6 filed on Dec. 20, 2017, the contents of which are fullyincorporated herein by reference.

TECHNICAL FIELD OF THE PRESENT INVENTION

The present invention relates to the field of pulley devices fortensioning idlers or runner rollers designed to interact with a chain ora belt, for example a distribution belt of an internal combustion engineof a vehicle.

BACKGROUND

Such rollers are usually used to keep a constant tension on the belt orchain in a determined range or to locally modify the path taken by thechain or belt. These are called respectively tensioning idlers or runnerrollers. In runner rollers, the pulley is mounted so as to rotate on ascrew or a spindle by means of a rolling bearing, the roller then beingattached directly or indirectly to the engine block or to an element ofa tensioning idler device, for example an articulated arm or aneccentric.

Document GB 190509598 discloses a pulley comprising male and femaleoverlapping parts which are interlocking relation and form a cylindricalouter portion intended to be in contact with a belt.

A major disadvantage of this pulley is that an annular recess is formedon the outer portion adapted to support the belt when the male andfemale parts are fastened together. There is therefore a risk of anearly wear of the belt.

It is also known by document GB 141 829 a pulley comprising a peripheralpart intended to be in contact with a belt, an inner part and aintermediate part between the inner and outer parts. The pulley istightened to the outer ring of bearing, but the pulley can slightlyaxially move during the service use of pulley device. Moreover, with apulley such as disclosed, the outer part may be deformed radiallyinwards by bending under the action of the belt.

It has been proposed in document DE 202005011230 U1 to house a dampingring within a C-shaped pulley, the damping element being dedicated todamp vibrations from the belt and being suitable to limit radial inwarddeformation of outer portion of the pulley. However, the pulley canstill be deformed under heavy loads.

BRIEF SUMMARY OF THE PRESENT INVENTION

The aim of the invention is to overcome these drawbacks by proposing apulley which is easy to install onto a bearing, of good rigidity,adapted to avoid an early wear of the belt, and permitting an efficientsupport of the belt.

To this end, the invention relates to a pulley device suitable for abelt of chain tensioning idler or runner roller, comprising a bearingand a pulley. The bearing comprises a rotatable outer ring and a fixedinner ring, the rings being coaxial. The pulley comprises at least onepulley part having in cross section an overall shape of a C, and havingan inner cylindrical portion with an inner cylindrical surface mountedon an outer cylindrical surface of outer ring of bearing, an outercylindrical portion having an outer cylindrical surface intended to bein contact with the belt or the chain, and a radial intermediate portionextending substantially radially between axial ends of inner and outercylindrical portions on one axial side of pulley device, the pulley partbeing formed integral and defining an open end on one axial side.

According to the invention, the outer cylindrical surface of outer ringof bearing is provided with at least one recess having in cross sectiona concave internal profile. Furthermore, the pulley part is providedwith at least one protruding portion which inwardly extends beyond theinner cylindrical surface of inner portion, the protruding portion beingreceived in a corresponding recess of outer ring so as to block pulleypart with respect to the outer ring in both axial directions.

According to further aspects of the invention which are advantageous butnot compulsory, such a pulley device may incorporate one or several ofthe following features:

-   -   The bearing is a rolling bearing, at least one row of rolling        elements being radially interposed between the inner ring and        the outer ring.    -   The rolling elements are balls.    -   The rolling elements are equally circumferentially spaced and        maintained by an annular cage.    -   The pulley is formed by only one pulley part.    -   The axial length of the inner portion of pulley part is at least        equal to 90% of the axial length of the outer cylindrical        surface of the outer ring of bearing.    -   The pulley devices comprises a pulley having two C-shaped pulley        parts mounted onto the outer cylindrical surface of outer ring        of bearing, open ends of the pulley parts axially facing each        other, each of the pulley parts being provided with a spacer.    -   The two pulley parts are symmetrical with respect to a        transverse radial plane passing through the center of the        bearing.    -   The total length of the inner portions of the two C-shaped        pulleys mounted onto the outer ring is at least equal to 90% of        the axial length of the outer cylindrical surface of the outer        ring.    -   The outer portion of pulley part is of greater axial length than        that of the inner portion, the outer portion protruding axially        on at least one axial side of the inner portion.    -   The pulley part is made from a stamped metal sheet or blank.    -   The recess provided to the outer cylindrical surface of outer        ring of bearing is an annular groove.    -   The recess is centered on a transverse radial plane passing        through the center of the bearing.    -   The recess is situated on outer cylindrical surface of outer        ring, in close vicinity of a radial lateral surface of the outer        ring.    -   The protruding portion is annular, and the recess is an annular        groove.    -   The pulley part comprises a plurality of circumferentially        spaced protruding portions, each being received by a        corresponding recess of outer ring.    -   The protruding portion provided to the pulley part consists in a        bent edge of free end of inner cylindrical portion of pulley        part, the bent edge being received by recess of outer ring.    -   The pulley part comprises a plurality of bent lugs, each being        received by a corresponding recess of outer ring.    -   The bent lugs radially inwardly extend from inner portion of        pulley part.    -   The bent lugs radially inwardly extend from outer portion of        pulley part, the bent lugs passing through the open end of        pulley part, the bent lugs radially extending along inner        portion edge and up to outer ring corresponding recess.    -   The pulley part comprises a plurality of protruding material        deformations formed by crimping of the inner portion of pulley        part, the protruding material deformations being each received        in a corresponding recess of outer ring.    -   The pulley part comprises a plurality of bent lugs radially        outwardly extending from the inner annular portion, free end of        the lugs coming in contact with an inner surface or bore of        outer annular portion, the lugs being provided with a cut inner        portion forming a lug in the same radial direction and radially        inwardly extending in a corresponding recess of outer ring of        bearing.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in correspondence with the annexedfigures, as illustrative examples, without restricting the object of theinvention. In the annexed figures:

FIG. 1 presents an axial section of a pulley device according to a firstembodiment of the invention;

FIG. 2 presents a perspective view of the pulley device originallyintroduced in FIG. 1;

FIG. 3 presents a detailed view of the pulley device originallyintroduced in FIG. 1;

FIG. 4 presents an axial section of a pulley device according to asecond embodiment of the invention;

FIG. 5 presents a detailed view of the pulley device originallyintroduced in FIG. 4;

FIG. 6 presents an axial section of a pulley device according to a thirdembodiment of the invention;

FIG. 7 presents a detailed view of the pulley device originallyintroduced in FIG. 6;

FIG. 8 presents an axial section of a pulley device according to afourth embodiment of the invention;

FIG. 9 presents a perspective view of the pulley device originallyintroduced in FIG. 8;

FIG. 10 presents a detailed view of the pulley device originallyintroduced in FIG. 8;

FIG. 11 presents an axial section of a pulley device according to afifth embodiment of the invention;

FIG. 12 presents a detailed view of the pulley device originallyintroduced in FIG. 11;

FIG. 13 presents a perspective view of a pulley provided to the pulleydevice originally introduced in FIG. 11; and

FIG. 14 presents a bottom view of the pulley originally presented inFIG. 13.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

The pulley device 1 as illustrated in FIGS. 1 to 3 is suitable for abelt or chain tensioning idler or runner roller, and comprises a pulley2 adapted to interact with a belt or chain (not shown) and a rollingbearing 3 with a geometric axis X1.

The rolling bearing comprises a fixed inner ring 4 and a rotatable outerring 5 between which are housed two rows of rolling elements 6 and 7,which in this case are balls, two annular cages 8, 9 respectivelymaintaining the circumferential spacing of the rolling elements 6, 7,and two annular seals 10, 11.

The inner ring 4 and the outer ring 5 are concentric and symmetric withrespect to a transverse radial plane Y3 passing through the center ofthe rolling bearing 3. The rings 4, 5 are advantageously of solid type.A solid type is to be understood as a ring obtained by machining withremoval of material, by machining, grinding, from a metal tube stock,bar stock, rough forgings and/or rolled blanks.

The inner ring 4 comprises a bore 12 dedicated to receive a fasteningscrew 13 (in dotted line) to fasten the device 1 on an external support.The inner ring further comprises an outer cylindrical surface 14 ontowhich toroidal circular raceways are formed, the raceways having incross section a concave internal profile adapted to the rolling elements6, 7.

The outer ring 5 comprises a cylindrical bore 15 onto which toroidalcircular raceways are formed, the raceways having in cross section aconcave internal profile adapted to receive the rolling elements 6, 7.The outer ring 5 further comprises an outer cylindrical surface 16.

The pulley 2 has two pulley parts 17, 18, both having in cross sectionan overall shape of a C.

The first pulley part 17 comprises an axial annular outer portion 19providing a cylindrical outer surface 20 designed to interact with aportion of the belt of the chain, and a cylindrical inner surface orbore 21.

The first pulley part 17 also comprises an axial annular inner portion22 providing a cylindrical inner surface or bore 23 into which the outercylindrical surface 16 of outer ring 5 of bearing 3 is mounted, and acylindrical outer surface 24.

The outer portion 19 is of larger diameter than that of the innerportion 22, the outer portion 19 radially surrounding the inner portion22. Advantageously, the outer portion 19 is of greater axial length thanthat of the inner portion 22, the outer portion 19 protruding axially onat least one axial side of the inner portion 22.

The first pulley part 17 further comprises an annular radialintermediate portion 25 extending substantially radially between axialends of inner and outer cylindrical portions 22, 19 on a first axialside of pulley device 1.

The first pulley part 17 then has in cross section an overall shape of aC, defining an open end 26 on one axial side of the pulley device 1. Thefirst pulley part 17 is formed integral.

The second pulley part 18 comprises an axial annular outer portion 27providing a cylindrical outer surface 28 designed to interact with aportion the belt of the chain, and a cylindrical inner surface or bore29.

The second pulley part 18 also comprises an axial annular inner portion30 providing a cylindrical inner surface or bore 31 into which the outercylindrical surface 16 of outer ring 5 of bearing 3 is mounted, and acylindrical outer surface 32.

The outer portion 27 is of larger diameter than that of the innerportion 30, the outer portion 27 radially surrounding the inner portion30. Advantageously, the outer portion 27 is of greater axial length thanthat of the inner portion 30, the outer portion 27 protruding axially onat least one axial side of the inner portion 30.

The second pulley part 18 further comprises an annular radialintermediate portion 33 extending substantially radially between axialends of inner and outer cylindrical portions 30, 27 on a second axialside of pulley device 1, the second axial side being axially opposite tothe first axial side.

The second pulley part 18 then has in cross section an overall shape ofa C, defining an open end 34 on one axial side of the pulley device 1.The second pulley part 18 is formed integral.

Advantageously, the pulley parts 17, 18 are both made of thin metalsheet or blank by folding, cutting and stamping.

Advantageously, the two C-shaped pulley parts 17, 18 are symmetricalwith each other with respect to the radial plane Y3. The free ends ofouter portions 19, 27 of first and second pulley parts 17, 18respectively come into contact in an axial direction, the open ends 26,34 respectively being axially open to each other. The two outercylindrical surfaces 20, 28 form a surface dedicated to interact withthe belt or the chain. The pulley 2 formed by the two pulley parts 17,18 arranged in axial contact with each other is suitable for guiding,supporting the belt of the chain with an efficient manner.

According to the invention, the outer cylindrical surface 20 of outerring 5 of bearing 3 is provided with an annular groove 35. The groove 35is centered on the transverse radial plane Y3 passing through the centerof the bearing 3.

Each of the pulley parts 17, 18 of pulley 2 further comprises aprotruding portion 37, 38, respectively. More precisely:

The inner annular portion 22 of first pulley part 17 comprises a freeedge 37 which is radially inwardly bent towards the outer ring 5 ofbearing 3. The the bent edge 37 is received by the annular groove 35 ofthe outer ring 5.

Similarly and symmetrically, the inner annular portion 30 of secondpulley part 18 comprises a free edge 38 which is radially inwardly benttowards the outer ring 5 of bearing 3. The the bent edge 38 is alsoreceived by the annular groove 35 of the outer ring 5.

The two bent edges 37, 38 are axially facing each other with respect tothe central radial plane Y3, and are both received in the same groove 35of outer ring 5.

The two parts 17, 18 of pulley 2 are then axially blocked in both axialdirection with respect to the outer ring 5 of bearing 3. Even in case ofheavy vibrations or shocks, the pulley 2 is prevented for axial movementand is suitable to efficiently support the belt of the chain for anincreased and efficient service life.

In a second embodiment of the invention shown in FIGS. 4 and 5, thepulley device 201 with a geometric axis X201 comprises a pulley 202having two C-shaped pulley parts 217, 218 mounted onto a rolling bearing203 having two annular grooves 235, 236 which interact withcorresponding protruding portions 237, 238 respectively of the first andsecond pulley parts 217, 218.

The rolling bearing 203 is essentially of similar construction as therolling bearing 3 of FIGS. 1 to 3. Rolling bearing 203 comprises a fixedinner ring 204 and a rotatable outer ring 205 between which are housedtwo rows of rolling elements 206 and 207, which in this case are balls,two annular cages 208, 209 respectively maintaining the circumferentialspacing of the rolling elements 206, 207, and two annular seals 210,211. The inner ring 204 and the outer ring 205 are concentric andsymmetric with respect to a transverse radial plane Y203 passing throughthe center of the rolling bearing 203.

The inner ring 204 comprises a bore 212 dedicated to receive a fasteningscrew 213 (in dotted line) to fasten the device 201 on an externalsupport. The inner ring further comprises an outer cylindrical surface214 onto which toroidal circular raceways are formed, the racewayshaving in cross section a concave internal profile adapted to therolling elements 206, 207.

The outer ring 205 comprises a cylindrical bore 215 onto which toroidalcircular raceways are formed, the raceways having in cross section aconcave internal profile adapted to receive the rolling elements 206,207. The outer ring 205 further comprises an outer cylindrical surface216.

The pulley 202 has two pulley parts 217, 218, both having in crosssection an overall shape of a C. The pulley 202 with pulley parts 217,218 is of essential similar construction as the pulley 2 with pulleyparts 17, 18, respectively, of FIGS. 1 to 3.

The first pulley part 217 comprises an axial annular outer portion 219providing a cylindrical outer surface 220 designed to interact with aportion of the belt of the chain, and a cylindrical inner surface orbore 221.

The first pulley part 217 also comprises an axial annular inner portion222 providing a cylindrical inner surface or bore 223 into which theouter cylindrical surface 216 of outer ring 205 of bearing 203 ismounted, and a cylindrical outer surface 224.

The outer portion 219 is of larger diameter than that of the innerportion 222, the outer portion 219 radially surrounding the innerportion 222. Advantageously, the outer portion 219 is of greater axiallength than that of the inner portion 222, the outer portion 219protruding axially on at least one axial side of the inner portion 222.

The first pulley part 217 further comprises an annular radialintermediate portion 225 extending substantially radially between axialends of inner and outer cylindrical portions 222, 219 on a first axialside of pulley device 201.

The first pulley part 217 then has in cross section an overall shape ofa C, defining an open end 226 on one axial side of the pulley device201. The first pulley part 217 is formed integral.

The second pulley part 218 comprises an axial annular outer portion 227providing a cylindrical outer surface 228 designed to interact with aportion the belt of the chain, and a cylindrical inner surface or bore229.

The second pulley part 218 also comprises an axial annular inner portion230 providing a cylindrical inner surface or bore 231 into which theouter cylindrical surface 216 of outer ring 205 of bearing 203 ismounted, and a cylindrical outer surface 232.

The outer portion 227 is of larger diameter than that of the innerportion 230, the outer portion 227 radially surrounding the innerportion 230. Advantageously, the outer portion 227 is of greater axiallength than that of the inner portion 230, the outer portion 227protruding axially on at least one axial side of the inner portion 230.

The second pulley part 218 further comprises an annular radialintermediate portion 233 extending substantially radially between axialends of inner and outer cylindrical portions 230, 227 on a second axialside of pulley device 201, the second axial side being axially oppositeto the first axial side.

The second pulley part 218 then has in cross section an overall shape ofa C, defining an open end 234 on one axial side of the pulley device201. The second pulley part 218 is formed integral.

Advantageously, the two C-shaped pulley parts 217, 218 are symmetricalwith each other with respect to the radial plane Y203.

According to this second embodiment of the invention, the outercylindrical surface 216 of outer ring 205 of bearing 203 comprises twoannular grooves 235, 236. The grooves 235, 236 are situated in closevicinity of opposite radial lateral surfaces of the outer ring 205. Theannular grooves 235, 236 are symmetric with respect to the centralradial plane Y203. The annular groove 235 is provided above the innerannular portion 222 of first pulley part 217, the annular groove 235being situated in close vicinity of a first lateral surface of outerring 5 on a first axial side. The annular groove 236 is provided abovethe inner annular portion 230 of second pulley part 218, the annulargroove 36 being situated in close vicinity of a second lateral surfaceof outer ring 205 on a second axial side which is axially opposite tothe first axial side.

Each of the pulley parts 217, 218 of pulley 202 further comprises aprotruding portion 237, 238, respectively. More precisely:

The inner annular portion 222 of first pulley part 217 comprises aplurality of material deformations 237 which are radially inwardlyprotruding towards the outer ring 205 of bearing 203. The protrudingportions 237 are formed by axial crimping of the the inner portion 222towards the opposite axial side. The protruding portions 237 aresituated in close vicinity of the radial intermediate portion 225 of thefirst pulley part 217, on the first axial side of device 201. Theprotruding portions 237 are circumferentially spaced around the innerportion 222 of first pulley part 217. The protruding portions 237 areeach received by the annular groove 235 of the outer ring 205.

Similarly and symmetrically, the inner annular portion 230 of secondpulley part 218 comprises a plurality of material deformations 238 whichare radially inwardly protruding towards the outer ring 205 of bearing203. The protruding portions 238 are formed by axial crimping of the theinner portion 230 towards the opposite axial portion. The protrudingportions 238 are situated in close vicinity of the radial intermediateportion 233 of the second pulley part 218, on the first axial side ofdevice 201. The protruding portions 238 are circumferentially spacedaround the inner portion 230 of second pulley part 218. The protrudingportions 238 are each received by the annular groove 235 of the outerring 205.

In the illustrated embodiments, the protruding portions 237, 238 areformed on the same radial planes. Alternatively, the protruding portionsmay be formed on different radial planes.

In a third embodiment of the invention shown in FIGS. 6 and 7, thepulley device 301 with a geometric axis X301 comprises a pulley 302having only one part mounted onto a rolling bearing 303 having oneannular groove 335 which interacts with a corresponding protrudingportion 337 of the and pulley 302.

The rolling bearing 303 is essentially of similar construction as therolling bearings 3 and 203 of FIGS. 1 to 5. Rolling bearing 303comprises a fixed inner ring 304 and a rotatable outer ring 305 betweenwhich are housed two rows of rolling elements 306 and 307, which in thiscase are balls, two annular cages 308, 309 respectively maintaining thecircumferential spacing of the rolling elements 306, 307, and twoannular seals 310, 311. The inner ring 304 and the outer ring 305 areconcentric and symmetric with respect to a transverse radial plane Y303passing through the center of the rolling bearing 303.

The inner ring 304 comprises a bore 312 dedicated to receive a fasteningscrew 313 (in dotted line) to fasten the device 301 on an externalsupport. The inner ring further comprises an outer cylindrical surface314 onto which toroidal circular raceways are formed, the racewayshaving in cross section a concave internal profile adapted to therolling elements 306, 307.

The outer ring 305 comprises a cylindrical bore 315 onto which toroidalcircular raceways are formed, the raceways having in cross section aconcave internal profile adapted to receive the rolling elements 306,307. The outer ring 305 further comprises an outer cylindrical surface316.

The pulley 302 has only one part having in cross section an overallshape of a C. The pulley 302 comprises an axial annular outer portion319 providing a cylindrical outer surface 320 designed to interact witha portion of the belt of the chain, and a cylindrical inner surface orbore 321.

The pulley 302 also comprises an axial annular inner portion 322providing a cylindrical inner surface or bore 323 into which the outercylindrical surface 316 of outer ring 305 of bearing 303 is mounted, anda cylindrical outer surface 324.

The outer portion 319 is of larger diameter than that of the innerportion 322, the outer portion 319 radially surrounding the innerportion 322. Advantageously, the outer portion 319 is of greater axiallength than that of the inner portion 322, the outer portion 319protruding axially on at least one axial side of the inner portion 322.

Advantageously, the axial length of the inner portion 322 of pulley 302is at least equal to 90% of the axial length of the outer cylindricalsurface 316 of the outer ring 305 of bearing 303.

The pulley 302 further comprises an annular radial intermediate portion325 extending substantially radially between axial ends of inner andouter cylindrical portions 322, 319 on a first axial side of pulleydevice 301.

The pulley 302 then has in cross section an overall shape of a C,defining an open end 326 on one axial side of the pulley device 301. Thepulley 302 is formed integral.

According to the invention, the outer cylindrical surface 316 of outerring 305 of bearing 303 comprises one annular groove 335. The groove 335is situated in close vicinity of a radial lateral surfaces of the outerring 305 which is axially opposite to the radial intermediate portion325 of pulley 302.

The inner annular portion 322 of pulley 302 comprises a plurality ofmaterial deformations 337 which are radially inwardly protruding towardsthe outer ring 305 of bearing 303. The protruding portions 337 areformed by axial crimping of the the inner portion 322 towards theopposite axial side. The protruding portions 337 are situated on theopposite axial side of the radial intermediate portion 325 of the firstpulley part 317. The protruding portions 337 are circumferentiallyspaced around the inner portion 322 of first pulley part 317. Theprotruding portions 337 are each received by the annular groove 335 ofthe outer ring 305.

As an alternate not shown, the groove on outer ring may be provided onthe axial side of the radial intermediate portion of pulley, theprotrusions being provided on the inner surface of inner portion on thisside, the protrusions being received in the groove.

In a fourth embodiment of the invention shown in FIGS. 8 to 10, thepulley device 401 comprises a pulley 402 having two C-shaped pulleyparts 417, 418 mounted onto a bearing 403 having one central annulargroove 435 which interact with corresponding bent lugs 437, 438respectively, which inwardly radially extend from outer portions 419,427 respectively, of the first and second pulley parts 417, 418.

The rolling bearing 403 is essentially of similar construction as therolling bearings 3, 203 and 303 of FIGS. 1 to 7. Rolling bearing 403comprises a fixed inner ring 404 and a rotatable outer ring 405 betweenwhich are housed two rows of rolling elements 406 and 407, which in thiscase are balls, two annular cages 408, 409 respectively maintaining thecircumferential spacing of the rolling elements 406, 407, and twoannular seals 410, 411. The inner ring 404 and the outer ring 405 areconcentric and symmetric with respect to a transverse radial plane Y403passing through the center of the rolling bearing 403.

The inner ring 404 comprises a bore 412 dedicated to receive a fasteningscrew 413 (in dotted line) to fasten the device 401 on an externalsupport. The inner ring further comprises an outer cylindrical surface414 onto which toroidal circular raceways are formed, the racewayshaving in cross section a concave internal profile adapted to therolling elements 406, 407.

The outer ring 405 comprises a cylindrical bore 415 onto which toroidalcircular raceways are formed, the raceways having in cross section aconcave internal profile adapted to receive the rolling elements 406,407. The outer ring 405 further comprises an outer cylindrical surface416.

The pulley 402 has two pulley parts 417, 418, both having in crosssection an overall shape of a C. The pulley 402 with pulley parts 417,418 is of essential similar construction as the pulley 2 with pulleyparts 17, 18, respectively, of FIGS. 1 to 3.

The first pulley part 417 comprises an axial annular outer portion 419providing a cylindrical outer surface 420 designed to interact with aportion of the belt of the chain, and a cylindrical inner surface orbore 421.

The first pulley part 417 also comprises an axial annular inner portion422 providing a cylindrical inner surface or bore 423 into which theouter cylindrical surface 416 of outer ring 405 of bearing 403 ismounted, and a cylindrical outer surface 424.

The outer portion 419 is of larger diameter than that of the innerportion 422, the outer portion 419 radially surrounding the innerportion 422. The outer portion 419 is of greater axial length than thatof the inner portion 422, the outer portion 419 protruding axially onthe axial side of radial plane Y403.

The first pulley part 417 further comprises an annular radialintermediate portion 425 extending substantially radially between axialends of inner and outer cylindrical portions 422, 419 on a first axialside of pulley device 401.

The first pulley part 417 then has in cross section an overall shape ofa C, defining an open end 426 on one axial side of the pulley device401. The first pulley part 417 is formed integral.

The second pulley part 418 comprises an axial annular outer portion 427providing a cylindrical outer surface 428 designed to interact with aportion the belt of the chain, and a cylindrical inner surface or bore429.

The second pulley part 418 also comprises an axial annular inner portion430 providing a cylindrical inner surface or bore 431 into which theouter cylindrical surface 416 of outer ring 405 of bearing 403 ismounted, and a cylindrical outer surface 432.

The outer portion 427 is of larger diameter than that of the innerportion 430, the outer portion 427 radially surrounding the innerportion 430. Advantageously, the outer portion 427 is of greater axiallength than that of the inner portion 430, the outer portion 427protruding axially on the axial side of radial plane Y403.

The second pulley part 418 further comprises an annular radialintermediate portion 433 extending substantially radially between axialends of inner and outer cylindrical portions 430, 427 on a second axialside of pulley device 401, the second axial side being axially oppositeto the first axial side.

The second pulley part 418 then has in cross section an overall shape ofa C, defining an open end 434 on one axial side of the pulley device401. The second pulley part 418 is formed integral.

Advantageously, the two C-shaped pulley parts 417, 418 are symmetricalwith each other with respect to the radial plane Y403.

According to this fourth embodiment of the invention, the outercylindrical surface 416 of outer ring 405 of bearing 403 comprises oneannular groove 435. The groove 435 is centered on the transverse radialplane Y403 passing through the center of the bearing 403.

The first pulley part 417 comprises a plurality of bent lugs 437 whichare radially inwardly extending from the outer portion 419 towards theouter ring 405. The lugs 437 form each a radial protruding portion thatextends through the open end 426 of the pulley part, in close vicinityof the central radial plane Y403. Free ends of the lugs 437 are eachreceived within the annular groove 435 of outer ring 405.

Similarly and symmetrically with respect to the central radial planeY403, the second pulley part 418 comprises a plurality of bent lugs 438which are radially inwardly extending from the outer portion 427 towardsthe outer ring 405. The lugs 438 form each a radial protruding portionthat extends through the open end 434 of the pulley part, in closevicinity of the central radial plane Y403. Free ends of the lugs 438 areeach received within the annular groove 435 of outer ring 405.

The lugs 437, 438 are axially adjacent by pairs. Tow lugs 437, 438 of apair are axially blocked between walls defined by the annular groove435. The two parts 417, 418 of pulley 402 are then axially blocked inboth axial direction with respect to the outer ring 405 of bearing 403.Even in case of heavy vibrations or shocks, the pulley 402 is preventedfor axial movement and is suitable to efficiently support the belt ofthe chain for an increased and efficient service life.

Thanks to this embodiment of the invention, when the belt or the chainexerts an inwards radial load on the outer portions 419, 427 of pulley402, the inner free edges of bent lugs 437, 438 are pressed in radialdirection against of the bottom surface of annular groove 435 providedto the outer ring 405 of bearing 403. The outer axial portions 419, 427are stiffened by the radial bent lugs 437, 438 respectively which aresupported in radial direction by outer ring 405. The lugs 437, 438permits to maintain in operating mode the radial position of the chainor the belt in contact with the outer surfaces 420, 428 of the outerportions 419, 427 respectively.

As an alternate not shown, the pulley may comprise only one pulley part,and the outer cylindrical surface of outer ring may comprise only oneannular groove which receives a plurality of bent lugs extending fromthe outer portion of the pulley. Advantageously, the annular groove andthe bent lugs are situated on the axial side of the open end of theC-shaped pulley.

In a fifth embodiment of the invention shown in FIGS. 11 to 14, thepulley device 501 comprises a pulley 502 having two C-shaped pulleyparts 517, 518 mounted onto a bearing 503 having one central annulargroove 535 which interact with corresponding bent lugs 537, 538respectively, which inwardly radially extend from inner portions 522,530 respectively, of the first and second pulley parts 517, 518.

The rolling bearing 503 is essentially of similar construction as therolling bearings 3, 203, 303 and 403 of FIGS. 1 to 10. Rolling bearing503 comprises a fixed inner ring 504 and a rotatable outer ring 505between which are housed two rows of rolling elements 506 and 507, whichin this case are balls, two annular cages 508, 509 respectivelymaintaining the circumferential spacing of the rolling elements 506,507, and two annular seals 510, 511. The inner ring 504 and the outerring 505 are concentric and symmetric with respect to a transverseradial plane Y503 passing through the center of the rolling bearing 503.

The inner ring 504 comprises a bore 512 dedicated to receive a fasteningscrew 513 (in dotted line) to fasten the device 501 on an externalsupport. The inner ring further comprises an outer cylindrical surface514 onto which toroidal circular raceways are formed, the racewayshaving in cross section a concave internal profile adapted to therolling elements 506, 507.

The outer ring 505 comprises a cylindrical bore 515 onto which toroidalcircular raceways are formed, the raceways having in cross section aconcave internal profile adapted to receive the rolling elements 506,507. The outer ring 405 further comprises an outer cylindrical surface516.

The pulley 502 has two pulley parts 517, 518, both having in crosssection an overall shape of a C. The pulley 502 with pulley parts 517,518 is of essential similar construction as the pulley 2 with pulleyparts 17, 18, respectively, of FIGS. 1 to 3.

The first pulley part 517 comprises an axial annular outer portion 519providing a cylindrical outer surface 520 designed to interact with aportion of the belt of the chain, and a cylindrical inner surface orbore 521.

The first pulley part 517 also comprises an axial annular inner portion522 providing a cylindrical inner surface or bore 523 into which theouter cylindrical surface 516 of outer ring 505 of bearing 503 ismounted, and a cylindrical outer surface 524.

The outer portion 519 is of larger diameter than that of the innerportion 522, the outer portion 519 radially surrounding the innerportion 522. The outer portion 519 is of greater axial length than thatof the inner portion 522, the outer portion 519 protruding axially onthe axial side of radial plane Y503.

The first pulley part 517 further comprises an annular radialintermediate portion 525 extending substantially radially between axialends of inner and outer cylindrical portions 522, 519 on a first axialside of pulley device 501.

The first pulley part 517 then has in cross section an overall shape ofa C, defining an open end 526 on one axial side of the pulley device501. The first pulley part 517 is formed integral.

The second pulley part 518 comprises an axial annular outer portion 527providing a cylindrical outer surface 528 designed to interact with aportion the belt of the chain, and a cylindrical inner surface or bore529.

The second pulley part 518 also comprises an axial annular inner portion530 providing a cylindrical inner surface or bore 531 into which theouter cylindrical surface 516 of outer ring 405 of bearing 503 ismounted, and a cylindrical outer surface 532.

The outer portion 527 is of larger diameter than that of the innerportion 530, the outer portion 527 radially surrounding the innerportion 530. Advantageously, the outer portion 527 is of greater axiallength than that of the inner portion 530, the outer portion 527protruding axially on the axial side of radial plane Y503.

The second pulley part 518 further comprises an annular radialintermediate portion 533 extending substantially radially between axialends of inner and outer cylindrical portions 530, 527 on a second axialside of pulley device 501, the second axial side being axially oppositeto the first axial side.

The second pulley part 518 then has in cross section an overall shape ofa C, defining an open end 534 on one axial side of the pulley device501. The second pulley part 518 is formed integral.

Advantageously, the two C-shaped pulley parts 517, 518 are symmetricalwith each other with respect to the radial plane Y503.

According to this fifth embodiment of the invention, the outercylindrical surface 516 of outer ring 505 of bearing 503 comprises oneannular groove 535. The groove 535 is centered on the transverse radialplane Y503 passing through the center of the bearing 503.

The first pulley part 517 comprises a plurality of bent lugs 537 whichare radially outwardly extending from the inner portion 522 towards theouter portion 519. The lugs 537 form each a radial protruding portionthat extends through the open end 526 of the pulley part, in closevicinity of the central radial plane Y503. The lugs 537 comprise each anupper free end 543 which comes in contact in radial direction againstthe inner surface or bore 521 of outer portion 519. Furthermore, a cut539 is provided to each of the lugs so as to define a lower free end541. The lower free ends 541 of lugs 537 come in contact in radialdirection against the bottom surface of annular groove 535 of outer ring505. The lugs 437 have the shape of a radial portion extending eachbetween an upper end 543 and a lower end 541, the lugs 537 beingradially blocked between outer portion 519 of first pulley part 517 andgroove 535 of outer ring 505.

Similarly and symmetrically, the second pulley part 518 comprises aplurality of bent lugs 538 which are radially outwardly extending fromthe inner portion 530 towards the outer portion 527. The lugs 538 formeach a radial protruding portion that extends through the open end 534of the pulley part, in close vicinity of the central radial plane Y503.The lugs 538 comprise each an upper free end 544 which comes in contactin radial direction against the inner surface or bore 529 of outerportion 527. Furthermore, a cut 540 is provided to each of the lugs soas to define a lower free end 542. The lower free ends 542 of lugs 538come in contact in radial direction against the bottom surface ofannular groove 535 of outer ring 505. The lugs 438 have the shape of aradial portion extending each between an upper end 544 and a lower end542, the lugs 538 being radially blocked between outer portion 527 ofsecond pulley part 518 and groove 535 of outer ring 505.

The lugs 537, 538 are axially adjacent by pairs. Lower free edges 541,542 of lugs 537, 538 of a pair are axially blocked between walls definedby the annular groove 535. The two parts 517, 518 of pulley 502 are thenaxially blocked in both axial direction with respect to the outer ring505 of bearing 503. Even in case of heavy vibrations or shocks, thepulley 502 is prevented for axial movement and is suitable toefficiently support the belt of the chain for an increased and efficientservice life.

Thanks to this embodiment of the invention, when the belt or the chainexerts an inwards radial load on the outer portions 519, 527 of pulley402, the inner cylindrical surfaces 521, 529 of the outer portions 519,5127 respectively, are pressed in radial direction against the upperfree edges 543, 544 of lugs 537, 538 respectively. Loads are transmittedthrough the radial portions of lugs 537, 538 to lower free edges 541,542 of the lugs. Lower free edges 541, 542 are then pressed in radialdirection against the bottom surface of groove 535 of outer ring 505.The outer axial portions 519, 527 are stiffened by the radial bent lugs537, 538 respectively which are supported in radial direction by outerring 505. The lugs 537, 538 permits to maintain in operating mode theradial position of the chain or the belt in contact with the outersurfaces 520, 528 of the outer portions 519, 527 respectively.

As an alternate not shown, the pulley may comprise only one pulley part,and the outer cylindrical surface of outer ring may comprise only oneannular groove which receives a plurality of bent lugs extending fromthe lower portion of the pulley. Advantageously, the annular groove andthe bent lugs are situated on the axial side of the open end of theC-shaped pulley.

Representative, non-limiting examples of the present invention weredescribed above in details with reference to the attached drawings. Thisdetailed description is merely intended to teach a person of skill inthe art further details for practicing preferred aspects of the presentteachings and is not intended to limit the scope of the invention.Furthermore, each of the additional features and teachings disclosedabove may be utilized separately or in conjunction with other featuresand teachings to provide improved pulley device.

Moreover, various features of the above-described representativeexamples, as well as the various independent and dependant claims below,may be combined in ways that are not specifically and explicitlyenumerated in order to provide additional useful embodiments of thepresent teachings.

What is claimed is:
 1. A pulley device suitable for a belt of one ofchain tensioning idler or runner roller, comprising: a bearingcomprising a rotatable outer ring and a fixed inner ring, the ringsbeing coaxial, and a pulley comprising: at least one pulley part having,in cross section, an overall shape of a “C”, and having an innercylindrical portion with an inner cylindrical surface mounted on anouter cylindrical surface of outer ring of bearing, an outer cylindricalportion having an outer cylindrical surface intended to be in contactwith the belt or the chain, and a radial intermediate portion extendingsubstantially radially between axial ends of inner cylindrical portionand outer cylindrical portion on one axial side of pulley device, thepulley part being formed integral and defining an open end on one axialside, wherein the outer cylindrical surface of outer ring is providedwith at least one recess having in cross section a concave internalprofile, and wherein the pulley part is provided with at least oneprotruding portion which inwardly extends beyond the inner cylindricalsurface of an inner portion, the protruding portion being received in acorresponding recess of the at least one recess of the outer ring so asto block the pulley part with respect to the outer ring in both axialdirections.
 2. (canceled)
 3. The pulley device according to claim 1,wherein the at least one recess is situated on outer cylindrical surfaceof outer ring, in close vicinity of a radial lateral surface of theouter ring.
 4. The pulley device according to claim 1, wherein the atleast one recess provided to the outer cylindrical surface of outer ringis an annular groove.
 5. (canceled)
 6. The pulley device according toclaim 1, wherein the pulley part comprises a plurality ofcircumferentially spaced protruding portions, each circumferentiallyspaced protruding portion being received by a corresponding recess ofthe at least one recess of the outer ring.
 7. (canceled)
 8. (canceled)9. The pulley device according to claim 1, wherein the pulley partcomprises a plurality of protruding material deformations formed by acrimping of the inner portion of the pulley part, the protrudingmaterial deformations being each received in a corresponding recess ofthe at least one recess of the outer ring.
 10. The pulley deviceaccording to claim 1, wherein the pulley part is made from one of astamped metal sheet or a blank.